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No. 75,000. PATENTED MAR. s, 1868.

G. E. DONHAM.

DENTISTS FLASK.

gumsgmm gaunt f Letters Patent No. 75,0Q0, dated MarehB, 1868.

IMPROVEMENT IN DENTISTS FLASK S.

at: Sttntalt tftitrlth it in tlgtst infers fiattnt mitt making mutt attin tam.

TO ALL WHOM IT MAY CONCERN:

Be it known that, 1-, GEORGE E. DONHAM, of East Abington,"in the countyof Plymouth, and State oi Massachusetts, have invented a new and usefulImprovement in Dentists Flasks; and I do hereby declare that h f g,taken in connection with the drawings which accompany and form part ofthis ecification, is a description of my invention, suificient to enablethose skilled in the art to practise it.

Since the employment of vulcanite'or hard rubber as a base by whichartificial teeth are united, and are titted; to the mouth, dentists havemade use of what they callfiasks, in which they take plaster moulds from.models' made from impressions taken from the mouths of patients, and inwhich moulds'withiu the flasks they vulcanize a compound of rubber, inconnection with artificial teeth, employing for this purpose a kind ofretort, heated by steam under pressure, which retort or vessel is calledby the dentists a vulcanizer. These flasks have heretofore been securedtogether, for the purpose of being submitted to the heat within thevulcanizer, by small screw-bolts passing through ears, forming portionsof, each section of each flask, three bolts being the number usuallyemployed with each flask. These bolts give agreat amount of trouble inthe manipulations connected with the manufacture, by vulcanizing, ofsets or partial sets oil artificial teeth, and in repairing the some, asevery practical dentist well knows- Besides this, there is no yieldwhatever in the bolts when employed as means for securing the flask;

Now, it is a desideratuu to have some elasticity in the means foruniting the parts of a. dentist's flask, for when the mould is packedwith soft-rubber compound, and the parts are then secured together, itis often the case that under the heat in the vulcanizer the rubber willmove or flow, in which case it is desirable that the parts of the mouldshould be capable of slight movement, so that the rubber shall be alwaysvulcanized under pressure. I I I With the bolts ordinarily employed forllolding'dentists flasks together in the vulcanizer there is noprovision for u yielding movement of the 'parts of the flask, .which itis the object of my'invention to secure, my invention consistingin thecombination, with a dentist's flask, and the means'for securing ittogether, of means for allowing its parts to yield, so that pressureupon the contents of the mouldin the flask can always be secured; also,in a spring-clamp, when so arranged as to surround the flask, and whenarranged to be used with provision for holding the parts of the flasktogether. The drawings show an illustration of the best embodi-- mont ofmy invention'known to me Figure 1 being an elevation of a flask providedwith a spring-clamp, in'which the means for holding the parts of theflask together are a screw and nut, the latter being integral with theclamp. Figure 2 is a plan of the organization seen in fig. 1. v a be areparts of the flask. dis a base-plate,' whi'ch may be considered as thelower part of the clamp, the side-pieces e 0 being pivoted to the plateby the rod), which passes through ears g, on the plate, these sidepiec'es being integral with the cross-piece h, which is a; spring, and is,of course, preferably of steel. In a nut formed in a boss, forgedintegral with the spring cross-piece h, a screw, 1', is fitted, whichmay be made with a handle as shown, or may have a head suitable forapplication of a wrench. To prevent the end of the screw from concavingthe flat surface of the flask on which it acts, I pivot the washer j tothe screw, and, by preference,make the lower face of the washer concave.Instead of the screw a wedge mightlhe insertedhetween the flask andtheltar It of the clamp, though the screw is preferable. I

An inferior way of embodying my invention would he to make the wnsherjus :t,s pring. making the clamp rigid, and the yielding connection ofthe parts of the flask inight be had so as to embody my invention, bydispensing with the clamp, and using springs in combination with theseparate bolts, by which tlent'ists' ll=isks are usually fastenedtogether. I f i v I claim, in combination with the parts of a dentistsflask, and means for securing said parts together, means for allowingthe parts to yield while retaining pressure on the contents of theflask, substantially as described- Also, the clamp when made so asto'yield, and arranged to be used withmeans for securing together theparts of a dentist's flask.

GEORGE E. DONHAM.

Witnesses:

A. W. Samar, B. E. DONHAI.

